I think they are pretty cool, but not a algae cure
IMO. Never had a problem with them eating polyps, but they are among a few crabs that are even this trustworthy. I like a small CUC but it isn't a cure for much except to dislodge food particles and some algaes that hang up in the rock work, but they digest this and poop it out anyway, so your filter is removing the excess food and algae nutrients regardless. Your just running it thru a crab first. There is a old joke there somewhere...
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